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Use of Digital Photography to Improve Composite Resin Selection and Material Placement

Jack D. Griffin, Jr., DMD

Polychromatic layering of composite resin enables the clinician to effectively recreate the innate properties of the tooth structures, provided the material characteristics and proper layering techniques are understood.1 Photographic evaluation of the patient’s dentition prior to and during direct composite placement can aid the clinician in identifying and replicating the anatomy of the natural tooth or teeth—thereby improving the precision of the restorations.

The greatest obstacles lie in determining where to place the various composites and envisioning the final result prior to placement. In a Class IV case, there are often variances in tooth colors, opacities, and texture that make material choice and placement a challenge for the practitioner.2 Digital photographs represent an efficient method for the clinician to plan, deliver, and enhance such restorations.3 As highlighted in the following technique, consultation using preoperative photographic images can provide the clinician with the vision needed to complete these restorations efficiently and with precision. Following placement, similar images can be taken, a non-distracted evaluation can be accomplished on a monitor, and a systematic outline for restoration enhancement can then be created.

Preoperative Blueprint Photography

In order to determine the true color and character of a tooth, distractions that can confuse the eye must be eradicated. Lighting, fatigue, influence of other tissues, and bias towards certain shades are all factors that must be overcome when focusing on the patient’s needs. Well-composed images that may be reviewed on a large monitor away from treatment room distractions can ensure an accurate plan is formulated.

In the treatment of single teeth, shade matching light control and tooth proximity are critical. The most important factor in a quality photographic worthy of color and incisal character evaluation is one in which light control is excellent. An overexposed image is essentially useless for tooth color and character evaluation.

Multiple digital photographs may be captured, loaded on a computer, and analyzed in approximately the same amount of time it takes for the assistant to explain treatment and try on composite shades. It is the author’s assertion that these few minutes may increase the accuracy of composite selection and reduce the trial and error involved with material placement.

Case Presentation

A 45-year-old female patient presented with a fractured central incisor and a composite restoration that had been placed the author (with the intent of providing more definitive treatment at a later date) 14 years previously. The restoration was a single-shaded hybrid composite that had served all functional purposes, but was unacceptable by today’s aesthetic standards regarding staining, wear, and unnatural character (Figure 1).4

Extraoral and wide intraoral images were taken to document the preoperative condition of the patient, but not necessarily to aid in composite placement. Despite the diligent effort by the staff to select shades, it was difficult to precisely match colors and tints directly on the patient, due to distractions that complicated proper evaluation.

Maximum close-up images were thus captured for thorough evaluation of tooth color, opacity, and incisal character. Gingival retractors were placed to prevent shadows during the exposure, and a contrastor was held behind the teeth to decrease the unnatural lighting of the teeth from behind during the flash. The digital photographs were loaded into a computer and viewed on a large monitor, where tooth color, tints, and variations in opacity were noted. The maximum zoom, combined with proper lighting control provided an excellent means of determining material placement (Figure 2).

To further ensure an accurate restorative prescription, non-tooth tissues that may distract the clinician’s eye were removed using digital imaging software (Figure 3). The adjusted image was displayed in the treatment room according to a written color prescription similar to those provided to a dental laboratory for the fabrication of an indirect restoration. This evaluation occurred while the assistant mocked up composites of varying shades and opacities to confirm the restoration prescription.

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Guiding Composite Layering with Digital Images

The existing composite was removed with a course diamond, and an irregular 3-mm to 4-mm bevel was placed to create a finish line that would conceal the fracture line following direct resin buildup. A composite system with three different opacities (dentin, enamel, and incisal) and customization tints was selected, and confirmation of composite shades and opacities were performed. To accomplish this, the clinician placed the resin material on a non-bonded tooth and cured it (Figure 4). The trial materials were then removed, the tooth was etched with a 37% phosphoric acid, and a light-cured bonding agent was applied and air thinned (Figure 5).

Using a more opaque composite, the first dentin layer was placed in an irregular form with lobes, using the digital photography as a guide. This layer would provide the majority of restoration’s strength, impart basic internal color, form the internal tooth lobes, and conceal most of the restoration/tooth junction (Figure 6). The microhybrid resin was used in order to improve the restoration’s ability to withstand intraoral forces; this layer would subsequently be covered with a microfill resin to instill a natural finish for the restoration.5,6 The dentin layer was undercontoured on the facial aspect to ensure that it remained 0.5 mm to 1 mm undercontoured after final shaping.

A low-opacity incisal layer, with 1 mm to 2 mm of overextension, was placed to restore the incisal edge (Figure 7). In order to build the innate characterizations of the tooth, the material was placed in an irregular manner, with basic shaping from a composite instrument. Irregular grooves were also placed on the facial prior to curing. Very little of the material covered the facial aspect of the dentin shade, which allowed room for the final increments of composite resin. The junction of the dentin and incisal shades was confined within the desired finished contour to ensure that the transition could be concealed by the definitive resin buildup. A thin layer of custom stain white opaque and honey-yellow was then mixed and applied asymmetrically with a small brush (Figures 8 and 9). The goal of this material was to provide the internal colors seen on the adjacent teeth and to help conceal transition areas between incisal and dentin composite.

A final layer of enamel B1 microfill composite was placed covering the entire restoration; this layer was slightly overcontoured to allow sufficient space for shaping and polishing. The restoration was light cured for 45 seconds from both the lingual and facial aspects.

Composite Finishing, Digital Critique, and Restoration Enhancements

Contouring was performed with a fine finish diamond bur and shaping disks. Embrasures were shaped and refined with three levels of finishing disks, and interproximal areas were finished with a composite knife and abrasive strips. Care was taken to enhance the facial anatomy by developing subtle developmental indentations with rubber polishing cups, disks, and polishing paste to provide a natural surface.7 Several digital photographs were then taken using the black contrastor, retractors, and maximum close-up as previously described (Figure 10).

The results were briefly evaluated away from the distractions (eg, office commotion, lighting, patient positioning) of the operatory that could have been an obstacle to an accurate review of the procedure. The image was analyzed on a computer monitor and obvious restoration deficiencies were marked (Figure 11). By referring to the analyzed images, the clinician was able to perform corrections in color, contour, and finish in a methodical and organized fashion to ensure that needed corrections were not missed (Figure 12). Photographic images formed the framework for these adjustments, and, when used properly, can often be the difference between an “acceptable” restoration and one that is “excellent” (Figure 13).

Conclusion

By using quality digital images as a blueprint for material selection, a guide for composite layering, and a tool for self-critique and restoration enhancement, excellent composites can become much more attainable for many practitioners. The precision and quality of the restoration are worth the few additional minutes taken to capture quality images for planning and executing direct composite procedures.